Chemically absorbed film comprising fluorocarbon chains

ABSTRACT

According to the invention, a fluorine-based or siloxane -based chemical adsorbed film containing a fluorocarbon compound can be formed on a given substrate surface in a laminated state and through chemical bonds (i.e., covalent bonds) with the substrate, it is possible to obtain a laminated film which has satisfactory adhesion to the substrate, is substantially pin-hole free and is very thin. Further, since the outermost layer may be substituted by fluorocarbon groups or hydroxyl groups, it is possible to obtain a film which has excellent water- and oil-repelling properties or hydrophilic and oil-repelling properties and can replace fluorine-based coating films, thus improving the performance of products requiring a coating having a water- and oil-repelling resistant property, weather-resistant property, wear-resistant property and so forth which are desirable in electric products, vehicles, industrial devices and so forth.

This application is a continuation of U.S. application Ser. No.08/053,660, filed Apr. 29, 1993, now abandoned, which is a continuationof U.S. application Ser. No. 07/872,185, filed Apr. 22, 1992, nowpending.

FIELD OF THE PRESENT INVENTION

The present invention relates to laminated chemically adsorbedmonomolecular films based on fluorocarbon and a method of manufacturingthe same.

More specifically, it concerns laminated chemically adsorbedmonomolecular films based on fluorocarbon with a purpose of replacingconventional fluorocarbon-based coating films in which it is desirableto have water- and oil-repelling properties or hydrophilic andoil-repelling properties and which may be used for electronic products,vehicles, industrial devices and so forth. It further relates tosiloxane-based monomolecular films or laminated monomolecular films.

More specifically, it concerns highly hydrophilic or water-repelling,heat-resistant. siloxane-based monomolecular films or laminatedmonomolecular films, which are formed to have thicknesses at thenanometer level for improving the durability of the surface ofhydrophilic substrates.

It further relates to a method of laminating a chemical monomolecularfilm onto a chemical monomolecular film, and also to materials forchemical adsorption.

BACKGROUND OF THE INVENTION

In the prior art, there are many methods of coating varioussilicone-based resins to improve the separating, water-repelling,electrically insulating, water-resistant, heat-resistant,humidity-resistant, weather-resistant, solvent-resistant and otherproperties concerning the durability of various substrates. However, thesilicone resins have low transparency. Therefore, if they are to becoated while retaining the color tone or luster of the substrate,coating should be very thin. However, the silicone resins have lowhardness and hence inferior scratch-resistant property. This means thatreducing the coating film thickness leads to deterioration of thedurability. Accordingly, it has been proposed to increase the hardnessof the coating film by making use of crosslinking reactions obtained byintroducing epoxy groups or vinyl groups into the molecules of thesilicone resins or increase the hardness of the coating film byincorporating such fillers as fine particles of silica, alumina,antimony, etc.

In another aspect, in an extensively employed well-known method ofmanufacturing fluorocarbon-based coating films, the surface of a metalsubstrate such as aluminum, steel or stainless steel is toughened bymeans of wire brushes or chemical etching, then a primer is coated. Apaint prepared by suspending fine particles of a fluorocarbon-basedmaterial such as ethylene polytetrafluoride in ethanol or the like, iscoated. Then, the substrate is dried and baked at a temperature of about400° C. for about one hour, thus fixing a fluorocarbon-based polymer onthe substrate surface.

With this method, the polymer coating can be readily obtained. However,since the polymer is bonded to the substrate merely by an anchor effect,its adhesion to the substrate is limited. In addition, the coating filmsurface is flattened because of the baking at a high temperature of 400°C. Therefore, a satisfactory water- and oil-repelling surface can not beobtained. Therefore, this method is insufficient for devices which needto have water- and oil-repelling coating films, such as electricproducts, vehicles and industrial devices.

Further, there are methods of plasma treatment for rendering the surfaceof fluorocarbon-based coating films hydrophilic. However, none of thempermits satisfactory characteristics to be obtained.

SUMMARY OF THE INVENTION

In the light of the foregoing, it is an object of the invention toprovide a method of manufacturing thin films, which have satisfactoryadhesion to the substrate, are substantially free from pin holes andhave excellent water- and oil-repelling properties or hydrophilic andoil-repelling properties. These films can replace fluorine-based coatingfilms, thus permitting improvement of the performance of devicesrequiring a coating having the water- and oil-repelling hydrophilic andoil-repelling, heat-resistant, weather-resistant or wear-resistantproperties. These properties are desirable in electric products,vehicles and industrial devices.

A further object of the invention is to provide a silicone-based coatingfilm, which can be thinly formed while retaining the color tone orluster of the substrate and has a superior scratch-resistant property.

According to a first aspect of the invention we provide a chemicallyadsorbed laminated film comprising a fluorocarbon chain formed on asubstrate surface by a covalent -Si- bond and a chemically adsorbedmonomolecular laminated film formed on said fluorocarbon chain film by a-Si- bond.

It is preferable in this invention that the chemically adsorbed chainscontain fluorine groups at an outermost end layer.

It is preferable in this invention that the covalent bond i s a -SiO-bond.

It is preferable in this invention that the surface of the outermostmonomolecular layer has hydroxyl groups, the laminated chemicallyadsorbed film having hydrophilic and oil-repelling properties.

It is preferable in this invention that the surface of the outermostmonomolecular layer has fluorocarbon groups, the laminated chemicallyadsorbed film having water- and oil-repelling properties.

It is preferable in this invention that the substrate is made of amember selected from the group consisting of metals, ceramics, glass andplastics.

According to a second aspect of the invention we provide a chemicallyadsorbed film comprising a siloxane-based molecular chain formed on asubstrate surface by a covalent -Si- bond and a chemically adsorbed filmlayer formed on said molecular chain oriented substantially verticallyto said substrate surface.

It is preferable in this invention that the chemically adsorbed filmlayer is a single monomolecular film or monomolecular laminated film.

It is preferable in this invention that the surface of the outermostmolecular layer has hydrophilic groups.

According to a third aspect of the invention we provide a method ofmanufacturing a laminated film by a chemical adsorption processcomprising the steps of:

(A) contacting a substrate surface with a non-aqueous solutioncontaining a chemical adsorption material having a fluorocarbon chainand end reactive groups, the substrate surface having active hydrogengroups;

(B) removing unreacted chemical adsorption material remaining on thesubstrate by washing the substrate with a non-aqueous organic solutionto form an adsorbed monomolecular precursor film:

(C) reacting unreacted chlorosilane groups on the adsorbed monomolecularprecursor film with water after the removal step;

(D) drying the adsorbed monomolecular precursor film to form an innerlayer:

(E) contacting the inner layer surface with a non-aqueous solutioncontaining a chemical adsorption material having a fluorocarbon chainand at least one end reactive group, the substrate surface having activehydrogen groups; and

(F) repeating steps (B) to (D) to form an outer layer.

It is preferable in this invention that the reactive group of thechemical adsorption material forming the outer layer is at least onemember of the group consisting of a halosilyl group, an alkoxysilylgroup, a halotitanium group, and an alkoxyl titanium group.

It is preferable in this invention that the chemical adsorption materialfor forming the inner layer is represented by the formula

    X.sub.p Cl.sub.3-p Si-R.sup.1 -(CF.sub.2).sub.n -R.sup.2 -SiX.sub.q CL.sub.3-q

(where n represents an integer, R¹ and R² represent an alkylene group ora substituted group containing a Si, an oxygen atom or a chemical bond,X represents a substituted group for a hydrogen atom, an alkyl oralkoxyl group, and p and q represent 1 or 2).

It is preferable in this invention that the chemical adsorption materialforming the outer layer is represented by the formula

    R.sup.3 -R.sup.4 -(CF.sub.2).sub.n -R.sup.5 -SiX.sub.p Cl.sub.3-p

(where n represents an integer, R³ represents an unsaturated group or adimethylsilyl group, R⁴ and R⁵ represent an alkylene group or asubstituted group containing a Si or an oxygen atom or a chemical bond,X represents a substituted group for a H, a halogen atom, an alkyl groupor an alkoxyl group, and p and q represent 1 or 2).

It is preferable in this invention that the chemical adsorption materialforming the outer layer is represented by the formula

    HSi(CH.sub.3).sub.2 -(CF.sub.2).sub.n -R.sup.6 -SiX.sub.p CL.sub.3-p

(where n represents an integer, R⁶ represents an alkylene group or asubstituted group containing a Si or an oxygen atom or a chemical bond,X represents a substituted group for a H, a halogen atom, an alkylgroup, or an alkoxyl group and p and q represent 1 or 2, and the HSi(CH₃)₂ -group is converted to the HO- group).

It is preferable in this invention that the chemical adsorption materialforming the outer layer is represented by the formula

    CH.sub.2 ═CH-(CF.sub.2).sub.n -R.sup.7 -SiX.sub.p CL.sub.3-p

(where n represents an integer, R⁷ represents an alkylene group or asubstituted group containing a Si or an oxygen atom or a chemical bond,X represents a substituted group for a H, a halogen atom, an alkyl groupor an alkoxyl group, and p represents 0 or 1 or 2, and the chlorosilylgroup is converted to an active functional group through energy beamirradiation in a reactive gas atmosphere).

It is preferable in this invention that the active hydrogen groups onthe surface are at least a member of the group consisting of a hydroxylgroup, an amino group, an imino group and a carboxyl group, and saidsubstrate is made of a material selected from the group consisting ofmetals, ceramics, plastics and glass.

It is preferable in this invention that the substrate has hydroxylgroups on the surface and is a plastic substrate with the surfacethereof rendered hydrophilic by treating in an oxygen-containing plasmaor corona atmosphere.

According to a third aspect of the invention we provide a method ofmanufacturing a chemically adsorbed monomolecular film by a chemicaladsorption process comprising the steps of:

(a) contacting a substrate surface with a non-aqueous solutioncontaining a chemical adsorption material having a straight chainsiloxane molecule and at least one reactive group, the substrate surfacehaving active hydrogen groups;

(b) removing unreacted chemical adsorption material remaining on thesubstrate by washing the substrate with a non-aqueous organic solutionto form an adsorbed monomolecular precursor film:

(c) reacting unreacted chlorosilane groups on the adsorbed monomolecularprecursor film with water after the removal step; and

(d) drying the adsorbed monomolecular precursor film to form amonomolecular film.

It is preferable in this invention that the chemical adsorption materialforming the monomolecular film is represented by the formula ##STR1##(where n represents an integer, Z represents an alkyl, an alkene, analkyne, an aryl, cycloalkyl, or those denaturation group, Q₁, and Q₂represents an alkyl group or a substituted group containing a Si or anoxygen atom).

It is preferable in this invention that the chemical adsorption materialforming the monomolecular inner layer film is represented by the formula

    Cl.sub.3-p SiX.sub.p O(A).sub.r SiX.sub.p Cl.sub.3-p, or ##STR2## (where n represents an integer, Q.sub.1, and Q.sub.2 represents an alkyl group or a substituted group containing a Si or an oxygen atom, A represents functional group containing SiO, X represents a substituted group for a H, halogen atom, an alkyl or an alkoxyl group, and p and q represent 1 or 2, r represents an integer), and the laminated film is formed on the inner layer film.

According to the invention, a siloxane-based or fluorine-basedmonomolecular laminated film containing at least fluorine can be formedon a given substrate surface in a laminated state and through chemicalbonds for covalent bonds) with the substrate, it is possible to obtain alaminated film, which has satisfactory adhesion to the substrate, issubstantially pin-hole free and has is very thin.

In addition, since the outermost layer may be substituted byfluorocarbon groups or hydroxyl groups, it is possible to obtain a film,which has excellent water- and oil-repelling properties or hydrophilicand oil-repelling properties and can replace fluorine-based coatingfilms, thus permitting improvement of the performance of productsrequiring a coating having water- and oil-repelling properties,hydrophilic and oil-repelling properties, heat-resistant property,weather-resistant property, wear-resistant property and so forth whichare desirable in electric products, vehicles, industrial devices and soforth. Further, the method of manufacture according to the inventionforms the laminated film efficiently, effectively and uniformly.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 (a)-(c) show a method of manufacturing a hydrophilic andoil-repelling laminated chemically adsorbed monomolecular film based oncarbon fluoride with the surface thereof covered by hydrophilic groupsas in example 1 of the invention.

FIG. 2 shows a method of manufacturing a water- and oil-repellinglaminated chemically adsorbed monomolecular film based on carbonfluoride with the surface thereof covered by carbon fluoride groups asin example 2 of the invention.

FIGS. 3 (a)-(d) show a method of manufacturing a hydrophilicoil-repelling laminated chemically adsorbed film based on carbonfluoride with the surface thereof covered by hydrophilic groups as inexample 3 of the invention.

FIG. 4 shows a method of manufacturing a water- and oil-repellinglaminated chemically adsorbed film based on carbon fluoride with thesurface thereof covered by carbon fluoride groups as in example 4 of theinvention.

FIGS. 5 (a)-(d) show a method of manufacturing a water- andoil-repelling laminated chemically adsorbed film based on carbonfluoride with the surface thereof covered by carbon fluoride groups asin example 5 of the invention.

FIGS. 6 (a)-(b) show a method of manufacturing a siloxane-basedchemically adsorbed monomolecular film as in example 6 of the invention.

FIGS. 7 (a)-(c) show a method of manufacturing a hydrophilicsiloxane-based laminated chemically adsorbed film as in example 7 of theinvention.

FIG. 8 shows a method of manufacturing a siloxane-based laminatedchemically adsorbed film as in example 8 of the invention.

DETAILED DESCRIPTION OF THE INVENTION

The laminated monomolecular film based on fluorocarbon according to theinvention may obtained by using almost any straight chainchlorosilane-based surface active material, the molecule of which haschlorosilane groups (i.e.. SiCl_(n) X_(3-n) groups, where X represents afunctional group) at opposite ends and a fluorocarbon chain in theremainder. It is particularly convenient to use, as the chemicaladsorption material based on carbon fluoride containing a plurality ofchlorosilyl groups at the molecular ends,

    X.sub.p Cl.sub.3-p Si-R.sup.1 -(CF.sub.2).sub.n -R.sup.2 -SiX.sub.q Cl.sub.3-q

(where n represents an integer, R¹ and R² represent an alkyl group or asubstituted group containing a silicon or an oxygen atom or a chemicalbon,. X represents a substituted group for a hydrogen atom or an alkylgroup, and p and q represent 1 or 2), or

    CF.sub.3 -(CF.sub.2).sub.n -Z-SiX.sub.q Cl.sub.3-q

(where n is an integer, Z represents an alkyl group or a substitutegroup containing a Si or an oxygen atom or a chemical bond, and qrepreesnts 0, 1 or 2).

For laminating other chemically adsorbed monomolecular layers based onfluorocarbon according to the invention, it is possible to use almostany straight chain chemical adsorption material based on chlorosilane,the molecule of which has a chlorosilane (SiCl_(n) X_(3-n), nrepresenting an integer ranging from 1 to 3, X representing asubstituted group) group at one end, an unsaturated group at the otherend and a carbon fluoride chain in the remainder. Particularlyconveniently, as the surface active material based on carbon fluoridemay be used

    R.sup.3 -R.sup.4 -(CF.sub.2).sub.n -R.sup.5 -SiX.sub.p Cl.sub.3-p

(where n represents an integer, R³ represents an unsaturated group or adimethylsilyl group, R⁴ and R⁵ represent an alkyl group or a substitutedgroup containing a silicon or an oxygen atom or a chemical bond, Xrepresents a substituted group for a hydrogen atom or an alkyl group,and p and q represent 1 or 2). As a reagent, for example, the followingcompounds may be used:

    Cl.sub.3 Si(CH.sub.2).sub.2 (CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3,

    CF.sub.3 (CF.sub.2).sub.7 (CH.sub.2).sub.2 SiCl.sub.3,

    HSi(CH.sub.3).sub.2 (CH.sub.2).sub.2 (CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3,

    and CH.sub.2 ═CH-(CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3.

According to the invention, a monomolecular film or a laminatedmonomolecular film based on siloxane having a thickness at the nanometerlevel may be formed as a layer chemically bonded to the substratesurface. It is thus possible to obtain a coating film, which will notspoil the color tone or luster instrinsic to the substrate and has anenhanced scratch-resistant property. This means that it is possible toimprove the separating property, water-repelling property, electricallyinsulating property, water-proof property, heat-resistant property,weather-resistant property and other durability properties of thesubstrate. Further, it is possible to make the surface of the filmwater-repelling or hydrophilic.

The siloxane-based monomolecular film having a thickness at thenanometer level may be obtained by a method, which comprises a step ofdipping and holding a thoroughly washed hydrophilic substrate in anon-aqueous organic solution containing a straight chainchlorosilane-based surface active material with the molecule thereofhaving a chlorosilane (SiCl_(n) X_(3-n), n represents an integer rangingfrom 1 to 3, X represens a substituted group) group at one end, forexample,

    V-(SiW.sub.2 O).sub.n -SiCl.sub.3

(where V and W represent a functional group, and n represents aninteger) for causing a reaction between molecules of the siloxane-basedchemical adsorption material (same to surface active material) andhydroxyl groups present on the substrate surface to thereby chemicallyadsorb the surface active material and a subsequent step of washingexcess siloxane-based surface active material away from the substrate byusing a non-aqueous organic solution and then reacting with water.

A hydrophilic siloxane-based monomolecular film, which is covered byhydrophilic hydroxyl groups, may be obtained by a method, whichcomprises a step of dipping a thoroughly washed hydrophilic substrate ina non-aqueous organic solution containing a straight chainchlorosilane-based surface active material having chlorosilyl groups atthe molecule ends, for example ##STR3## (where Q₁, Q₂ represents afunctional group, and n represents an integer), thereby chemicallyadsorbing the siloxane-based surface active material to the substratesurface, and a subsequent step of washing excess siloxane-based surfaceactive material away from the substrate by using a non-aqueous organicsolution and then reacting with water.

Subsequent to this process, a siloxane-based monomolecular two-layerfilm having a water-repelling surface, may be obtained by a method,which comprises a step of dipping the substrate in a non-aqueous organicsolution containing a straight chain chlorosilane-based surface activematerial, the molecule of which has a chlorosilane group at one end, forexample,

    Cl.sub.3 SiO-(SiQ.sub.2 O).sub.n -SiCl.sub.3

(where Q represents an alkyl group, and n represents an integer), forcausing a reaction between molecules of the siloxane-based surfaceactive material and hydroxyl groups present on the substrate surface anda subsequent step of washing excess siloxane-based surface activematerial away from the substrate by using a non-aqueous organic solutionand then reacting with water. Meanwhile, a siloxane-based monomoleculartwo-layer film, which is covered by hydrophilic hydroxyl groups, may beobtained by using a straight chain chlorosilane-based surface activematerial, the molecule of which has a chlorosilane group at one end, forinstance

    Cl.sub.3-p SiX.sub.p O-(A).sub.n -SiX.sub.q Cl.sub.3-p

(where A represents an alkylene group, and n represents an integer, inlieu of the straight chain chlorosilane-based surface active material,the molecule of which has a chlorosilane group at one end.

In carrying out our invention in one preferred mode, the monomolecularfilm is formed by utilizing the reaction between an active hydrogengroup such as a hydroxyl group (-OH), an amino group (-NH₂), an iminogroup (═NH), a carboxyl group (-COOH) on the substrate surface, and afunctional group, such as a chlorosilyl group, at one end of themolecule to be adsorbed. The rate of formation of the adsorbed film andthe saturated adsorption of the film are greately affected by theconcentration of the adsorbed material, the temperature, the speed ofreaction between the substrate surface and the adsorption molecules, theshape of the adsorption molecules, the number of hydroxyl groups on thesubstrate surface, the state of the substrate surface and so forth.

Since the chemically adsorbed film according to the invention utilizesmolecules having functional groups capable of reacting with activehydrogen groups, the atmosphere of the adsorption film formation step isas low in relative humidity as possible. Desirably, the humidity is at aperfectly dry state.

The substrate according to the invention is by no means limited so longas its surface contains active hydrogen groups such as -OH, -COOH, -NH₂or -NH groups. Examples of the substrate material are various kinds ofglass such as quartz glass, fluoride glass and metal glass, metals suchas aluminum, iron, stainless steel, titanium, semiconductors such assilicon and germanium, and plastics such as polypropylene, polystyrene,polyethylene and acryl resin. Substrates with less surface hydrophilicgroups, for instance plastic substrates, may be made suitable accordingto the invention by increasing the hydrophilic groups through ordinarychemical treatment means such as ozone oxidation or electron beamirradiation. Polyimide resins and polyurethane resins have surface iminogroups (═NH) and therefore do not require any pre-treatment. As analternative pre-treatment means effective for the surface of substratessuch as glass, metals, ceramics and plastics, silica (SiO₂) can bedeposited or polyhalogenated silane, such as dichlorosilane,trichlorosilane and tetrachlorosilane, can be coated and reacted withwater. The pre-treatment can be with or without washing with anon-aqueous solution and increases the formation of silanol (-SiOH)groups on the substrate surface. By so doing, the chemical adsorbingmaterial can be reacted at a high concentration.

According to the invention, any organic solvent may be used so lone asit is a non-aqueous organic solvent, does not attack the substrate andpermits sufficient dissolution of the chemical adsorbing material, sincethe chemical adsorbing material is reacted with hydrous molecules.Examples of the organic solvent are long chain alkyl-based solvents,aromatic hydrocarbon-based solvents, aliphatic hydrocarbon-basedsolvents and halogen-containing solvents.

EXAMPLE 1

As shown in FIG. 1(a), a hydrophilic glass substrate 11 was prepared. Ifplastic or like water-repelling substrates are to be dealt with insteadof metal, ceramic, glass and other substrate with the surface thereofoxidized, their surface may be oxidized to be hydrophilic by treatingthem with dichromic acid. After a thorough drying, the substrate wasdipped and held for about two hours in a solution of 80 wt. % hexadecane(or toluene or xylene or bicyclohexyl), 12 wt. % of carbon tetrachlorideand 8 wt. % of chloroform, the solution containing a chemical adsorbedmaterial having two trichlorosilyl groups at molecule ends, for example,

    Cl.sub.3 Si(CH.sub.2).sub.2 (CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3

to a concentration of about 2 wt. %. Since the surface of the glasssubstrate 11 contained many hydroxyl groups 12, a hydrochloric acidelimination reaction (dehydrochlorination reaction) was thus broughtabout between -SiCl groups at either end of the molecules of thechemical adsorbed material, producing bonds represented by the formula[1]; ##STR4## over the entire substrate surface.

Subsequently, the substrate was washed well using an organic solvent(i.e. chloroform) to remove excess chemical adsorbed material remainingon its surface, and then washed with water and dried. As a result, asiloxane-based monomolecular layer 13 represented by the formula [2];##STR5## was formed such that it was secured by chemical bonds (orcovalent bonds) to the substrate surface. The chemical bond is via asiloxane bond. The formation of the chemically adsorbed monomolecularfilm was measured by FTIR spectrometry and the thickness was about 1.5nanometers (nm), as shown in FIG. 1(b). It was firmly bonded such thatit did not separate.

By subsequently carrying out the steps from the chemical adsorption stepto the water washing and drying step, a bi-layer (di-molecular) 14 asshown in FIG. 1(c) was obtained. The formation of the chemicallyadsorbed monomolecular film was measured by FTIR spectrometry and thethickness was about 3.0 nanometers (nm). It was firmly bonded such thatit did not separate.

Likewise, by repeating the steps from the chemical adsorption step tothe water washing and drying step for a required number of layers, alaminated monmolecular chemically adsorbed film based on fluorocarbonwas obtained, the surface of which was covered by hydroxyl groups, andwhich was hydrophilic and oil-repelling and had a very high adhesion.

EXAMPLE 2

After forming the hi-layer laminated monomolecular film in Example 1,the substrate with the laminated film was dipped and held for about twohours in a solution of 80 wt. % of hexadecane (or toluene or xylene orbicylcohexyl), 12 wt. % of carbon tetrachloride and 8 wt. % ofchloroform, the solution containing a chemically adsorbed material, themolecule of which had a trichlorosilyl group at one end and had theother end substituted by carbon trifluoride, for example

    CF.sub.3 (CF.sub.2).sub.7 -(CH.sub.2).sub.2 -SiCl.sub.3

to a concentration of 2 wt. %. Since the surface of the laminated filmcontained many hydroxyl groups 22, a dehydrochlorination reaction wasbrought about between the SiCl groups of the chemical adsorbed materialand the hydroxyl groups of the laminated film, thus producing bondsrepresented by the formula [3] over the entire substrate surface.##STR6##

The substrate was then washed well with an organic solvent (i.e.,chloroform) to remove non-reacted chemical adsorbed material remainingon its surface, and then washed with water. As a result, a monomolecularlayer 22 represented by the formula [4] was formed. ##STR7##

Thus, a laminated chemically adsorbed monomolecular film 22 based onfluorocarbon was obtained, the surface of which was covered byfluorocarbon groups, and which was excellent water- and oil-repellingand had a very high adhesion, as shown in FIG. 2.

While in the above Examples 1 and 2,

    Cl.sub.3 Si(CH.sub.2).sub.2 (CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3 and

    CF.sub.3 (CF.sub.2).sub.7 (CH.sub.2).sub.2 SiCl.sub.3

were used, other compounds may be used as well. Examples of suchcompounds are ##STR8##

EXAMPLE 3

As shown in FIG. 3(a), a hydrophilic ceramic substrate 31 was prepared.After thoroghly drying, the substrate was dipped and held for about twohours in a solution of 80 wt. % hexadecane for toluene or xylene orbicyclohexyl) , 12 wt. % a of carbon tetrachloride and 8 wt. %chloroform, the solution containing a chemical adsorbed material, themolecule of which had a trichlorosilyl group at one end and had a vinylgroup at the other end, for example;

    CH.sub.2 ═CH-(CF.sub.2).sub.6 -(CH.sub.2).sub.2 SiCl.sub.3

Since the surface of the ceramic substrate contained many hydroxylgroups 32, a dehydrochlorination reaction was brought about between the-SiCl groups of the chemical adsorbed material and the hydroxyl groupsof the substrate surface. A monomolecular layer 33 represented by theformula [5]; ##STR9## was formed over the entire substrate surface.

The substrate was then washed with freon 113 to remove the unreactedmaterial remaining on the surface, followed by washing with water orexposing to air containing moisture. The -SiCl group was changed to a-SiOH group as in formula [6]. ##STR10## Each silanol group (-SiOH) wasthen dehydrated and crosslinked to form a siloxane bond (-SiO-) afterdrying as in formula [7]. Drying temperature may be room temperature orabove. ##STR11##

An adsorbed monomolecular film was obtained on the surface of thesubstrate as shown FIG. 3(b). The adsorbed monomolecular film has afluorocarbon group 33 and is chemically bonded (i.e., covalently bonded)to the substrate. The chemical bond is via a siloxane bond. Theformation of chemically adsorbed monomolecular film was measured by FTIRspectrometry and the thickness was about 1.5 nanometers (nm). It wasfirmly bonded such that it did not separate. FIG. 3(b).

The substrate was irradiated with an energy beam such as electron beam,ion beam, gamma ray or ultraviolet ray in a reactive gas atmosphere (forexample irradiation with about 5 Mrads. of electron beam in air). As aresult, a monomolecular layer 34 represented by formulas [8] to [10];##STR12## was formed such that it was chemically bonded to the surface,as shown in FIG. 3(c).

By carrying out the steps from the chemical adsoprtion step using

    CH.sub.2 ═CH-(CF.sub.2).sub.6 -(CH.sub.2).sub.2 SiCl.sub.3

to the water washing step, a bi-layer film 35 containing fluorocarbongroups as shown in FIG. 3(d) was obtained.

Likewise, by repeating the steps from the chemical adsorption step tothe energy beam irradiation step for a desired number of layers, alaminated chemically adsorbed monomolecular film was obtained, thesurface of which was covered by hydroxyl groups and imino groups, andwhich was hydrophilic and oil-repelling and had a very high adhesion.

EXAMPLE 4

After forming the single-layer monomolecular film in Example 3, thesubstrate with the laminated film was dipped and held for two hours in asolution of 80 wt. % of hexadecane (or toluene or xylene orbicyclohexyl), 12 wt. % of carbon tetrachloride and 8 wt. % ofchloroform, the solution containing a chemical adsorbed material withthe molecule thereof having a trichlorosilyl group at one end and havingthe other end substituted by carbon trifluoride, for example,

    CF.sub.3 -(CF.sub.2).sub.7 -(CH.sub.2).sub.2 -SiCl.sub.3

to a concentration of about 2 wt. %. Since the surface of the laminatedfilm contained many hydroxyl and imino groups, a dehydrochlorinationreaction was thus brought about between the -SiCl groups of the chemicaladsorbed material and the hydroxyl groups of the laminated film. Bondsrepresented by the formula [11]; ##STR13## were thus produced over theentire substrate 41 surface.

Subsequently, the substrate was washed well with an organic solvent(i.e., chloroform) to remove non-reacted chemical adsorbed materialremaining on its surface. A laminated chemically adsorbed monomolecularfilm 42 based on carbon fluoride was obtained by the formula [12];##STR14## which had its surface covered by carbon fluoride groups, wasexcellent water- and oil-repelling and had a very high adhesion, asshown in FIG. 4.

By using

    Cl.sub.3 Si(CH.sub.2).sub.2 (CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3

the last chemical adsorption step of this example, a laminatedchemically adsorbed monomolecular film based on fluorocarbon, thesurface of which is hydrophilic, was obtained.

Further, while in the above Examples 3 and 4, there were used

    CH.sub.2 ═CH-(CF.sub.2).sub.6 -(CH.sub.2).sub.2 -SiCl.sub.3

    and CF.sub.3 -(CF.sub.2).sub.7 -(CH.sub.2).sub.2 -SiCl.sub.3,

other compounds may be utilized as well, for example

    CH.sub.2 ═CH-(CF.sub.2).sub.8 -(CH.sub.2 .sub.2 -SiCl.sub.3,

    CF.sub.3 -(CF.sub.2).sub.9 -(CH.sub.2).sub.2 -SiCl.sub.3,

    CF.sub.3 -(CF.sub.2).sub.5 -(CH.sub.2).sub.2 -SiCl.sub.3,

    CF.sub.3 CH.sub.2 O(CH.sub.2).sub.15 SiCl.sub.3,

    CF.sub.3 (CH.sub.2).sub.2 Si(CH.sub.3).sub.2 (CH.sub.2).sub.15 SiCl.sub.3,

    and CF.sub.3 COO(CH.sub.2).sub.15 SiCl.sub.3.

EXAMPLE 5

As shown in FIG. 5(a), a hydrophilic aluminium substrate 51 wasprepared. After drying well, the substrate was dipped and held in asolution of 80 wt. % of hexadecane (or toluene or xylene orbicyclohexyl) 12 wt. % of carbon tetrachloride and 8 wt. % of chloroformcontaining a chemical adsorbed material with the molecule thereof havinga trichlorosilyl group at one end and having dimethylsilyl (HSi(CH₃)₂ -)group at the other end, for example,

    HSi(CH.sub.3).sub.2 (CH.sub.2).sub.2 (CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3

to a concentration of about 2 wt. %. Since the surface of thehydrophilic substrate contained many hydroxyl groups 52, adehydrochlorination reaction was brought about between the -SiCl groupsof the chemical adsorbed material and the hydroxyl groups of thesubstrate surface. A monomolecular layer 53 as represented by formula[13]; ##STR15## was formed over the entire substrate surface.

The substrate was then washed well with an organic solvent (i.e.,chloroform) to remove non-reacted chemical adsorbed material remainingon its surface. A laminated chemically adsorbed monomolecular film 53based on carbon fluoride was obtained by the formula [14]; ##STR16##which had its surface covered by hydrocarbon groups, was water-repellingand had a very high adhesion, as shown in FIG. 5(b).

The substrate was then treated for about 10 hours with a H₂ O₂ solutioncontaining KF, KHCO₃, MeOH and T HF. A monomolecular layer 54represented by the formula [15]; ##STR17## was thus formed such that itwas chemically bonded to the surface, as shown in FIG. 5(c).

By subsequently carrying out the steps from the chemical adsorption stepusing

    HSi(CH.sub.3).sub.2 (CH.sub.3).sub.2 (CF.sub.2).sub.6 (CH.sub.2 .sub.2 SiCl.sub.3

to the H₂ O₂ treatment step, a laminated molecular film 55 containingcarbon fluoride groups shown in FIG. 5(d) was obtained.

Likewise, by repeating the steps from the chemical adsorption step tothe H₂ O₂ treatment step for a desired number of layers, a laminatedchemically adsorbed monomolecular film based on carbon fluoride could beobtained, which had its surface covered by hydroxyl groups, washydrophilic and oil-repelling and had a very high adhesion.

By using

    CF.sub.3 -(CF.sub.2).sub.7 -(CH.sub.2).sub.2 -SiCl.sub.3

in the last chemical adsorption step in the above example, a laminatedchemically adsorbed monomolecular film based on carbon fluoride, thesurface of which is excellent water- and oil-repelling, can be obtained.

EXAMPLE 6

A polycarbonate substrate having a thickness of 1.2 mm and a diameter of60 mm was fixed to another polycarbonate substrate, using a UV-settingadhesive. The substrate thus obtained was oxygen plasma treated in a UVdry stripper ("UV-1" manufactured by Samco International) at an oxygenflow rate of 1 1/min. for 10 minutes to oxidize the surface. Thesubstrate was dipped and held in a freon 113 solution containing 10⁻²mol/l of

    Cl.sub.3 Si(CH.sub.2).sub.2 (CF.sub.2).sub.6 (CH.sub.2).sub.2 SiCl.sub.3

as the chlorosilane-based chemical adsorbed material containing afluorocarbon group. This step was carried out in a nitrogen atmosphereat room temperature. Since the surface of the substrate containedhydroxyl groups, a dehydrochlorination reaction between the chlorosilylgroups of the chlorosilane-based chemical adsorbed material and thehydroxyl groups formed covalent bonds on the surface. This reaction isrepresented in above formula [1].

The substrate was then washed with freon 113 to remove the unreactedmaterial remaining on the surface, followed by washing with water orexposing to air containing moisture. The -SiCl group was changed to a-SiOH group. Each silanol group (-SiOH) was then dehydrated andcrosslinked to form a siloxane bond (-SiO-) after drying as in aboveformula [2]. Drying temperature may be room temperature or above.

An adsorbed monomolecular film was obtained on the surface of thesubstrate. The adsorbed monomolecular film has a fluorocarbon group andis chemically bonded (i.e., covalently bonded) to the substrate. Thechemical bond is via a siloxane bond. The formation of the chemicallyadsorbed monomolecular film was measured by FTIR spectrometry and thethickness was about 1.5 nanometers (nm). It was firmly bonded such thatit did not separate.

By subsequently carrying out the steps from the chemical adsorption stepto the water washing and drying step, a bi-layer was obtained. Theformation of the chemically adsorbed monomolecular film was measured byFTIR spectrometry and the thickness was about 3.0 nanometers (nm). Itwas firmly bonded such that it did not separate.

Likewise, by repeating the steps from the chemical adsorption step tothe water washing and drying step for a required number of layers, alaminated monmolecular chemically adsorbed film based on fluorocarbonwas obtained, the surface of which was covered by hydroxyl groups, andwhich was hydrophilic and oil-repelling and had a very high adhesion.

EXAMPLE 7

A Nylon-6,6 resin substrate having a thickness of 5.0 mm and a area of100 mm×100 mm was dipped and held for about 30 minutes in a solutionprepared by dissolving 1% by weight of a material containing a pluralityof chlorosilyl groups, e.g.,

    SiCl.sub.4, SiHCl.sub.3, SiH.sub.2 Cl.sub.2, and

    Cl(SiCl.sub.2 O).sub.n Cl.sub.3

(where n represents an integer in a range from 1 to 20), being small inmolecular size and greatly reactive with respect to imino groups, thusrendering the surface uniformly hydrophilic in a non-aqueous solvent,e.g., freon 113 solvent. As a result, a dehydrochlorination reaction wasbrought about due to imino >NH groups more or less present at thesurface of the substrate, whereby a chlorosilane monomolecular film ofthe material containing a plurality of trichlorosilyl groups was formed.

As an example, using SiCl₄ as the material containing a plurality ofchlorosilyl groups, a dehydrochlorination reaction was brought about onthe surface due to a small quantity of hydrophilic -OH groups beingexposed at the substrate surface. Molecules represented by formulas [16]and/or [17] were formed. ##STR18## Those bonds were connected to thesubstrate surface by -SiO- bonds.

Subsequently, the substrate was washed with a non-aqueous solvent, e.g.,freon 113 to remove unreacted SiCl₄ molecules, and then with water thusobtaining a siloxane monomolecular film at the substrate surface asshown by formulas [18] and/or [19]. ##STR19##

The monomolecular film was completely bonded by chemical bonds of -SIN<to the part surface and did not separate. In addition, its surfacecontained numerous silanol (-SiOH) bonds corresponding to about threetimes the initial number of imino groups.

As a further example, it was repeated same as example 6. An adsorbedmonomolecular film was obtained on the surface of the substrate. Theadsorbed monomolecular film has a fluorocarbon group and is chemicallybonded (i.e., covalently bonded) to the substrate. The chemical bond isvia a -SIN< bond. The formation of the chemically adsorbed monomolecularfilm was measured by FTIR spectrometry and the thickness was about 1.5nanometers (nm). It was firmly bonded such that it did not separate.

By subsequently carrying out the steps from the chemical adsorption stepto the water washing and drying step, a bi-layer was obtained. Theformation of the chemically adsorbed monomolecular film was measured byFTIR spectrometry and the thickness was about 3.0 nanometers (nm). Itwas firmly bonded such that it did not separate.

Likewise, by repeating the steps from the chemical adsorption step tothe water washing and drying step for a required number of layers, alaminated monmolecular chemically adsorbed film based on fluorocarbonwas obtained, the surface of which was covered by hydroxyl groups, andwhich was hydrophilic and oil-repelling and had a very high adhesion.

EXAMPLE 8

As shown in FIG. 6(a), a hydrophilic glass substrate 61 was prepared. Ifplastic or like oil-repelling substrates are dealt with instead ofmetal, ceramic, glass or other substrates with the surface thereofoxidized, their surface may be oxidized to be hydrophilic by treatingthem with dichromic acid. After thoroghly drying, the substrate wasdipped and held in a solution of 80 wt. % of cyclohexane (orn-hexadecane. toluene, xylene or bicyclohexyl), 12 wt. % of carbontetrachloride and 8 wt. % of chloroform, the containing a chemicaladsorbed material having a single chlorosilyl group at a molecular end,for example,

    (CH.sub.3).sub.3 SiO-(Si(CH.sub.3).sub.2 O).sub.6 -SiCl.sub.3

at a concentration of 4 wt. %. Since the surface of the hydrophilicsubstrate contains many hydroxyl groups 62, a dehydrochlorinationreaction was brought about between the -SiCl groups at either end of thechemical adsorbed material and the hydroxyl groups of the substrate.Bonds represented by the formula [20]; ##STR20## were thus produced overthe entire substrate surface.

The substrate was then washed well with an organic solvent to removenon-reacted chemical adsorbed material remaining on the substratesurface, and then washed with water. Thus, a siloxane-basedmonomolecular layer 63 was formed such that it was chemically bonded tothe surface, as shown in FIG. 6(b), represented by the formula [21];##STR21## were thus produced over the entire substrate surface, thus wasformed such that it was chemically bonded to the substrate surface andhad a thickness of about 2.5 nanometers (nm).

EXAMPLE 9

As shown in FIG. 7(a), a hydrophilic ceramic substrate 71 was prepared.If plastic or like water-repelling substrates are to be dealt withinstead of metal, ceramic, glass and other substrates with the surfacethereof oxidized, their surface may be oxidized to be hydrophilic bytreating them with dichromic acid. Then, after thoroughly drying, thesubstrate was dipped and held in a solution of 80 wt. % of cyclohexane(or n-hexadecanetoluene or xylene or bicyclohexyl), 12 wt. % of carbontetrachloride and 8 wt. % of chloroform, the solution containing achemical adsorbed material with the molecule thereof having twochlorosilyl groups at molecule ends, for example

    Cl.sub.3 SiO-(Si(CH.sub.3).sub.2 O).sub.6 -SiCl.sub.3

to a concentration of about 4 wt. %. Since the surface of thehydrophilic substrate contained many hydroxyl groups 72, adehydrochlorination reaction was brought about between -SiCl groups ateither end of the chemical adsorbed material and hydroxyl groups of thesubstrate surface. A monomolecular layer 73 represented by the formula[22]; ##STR22## was thus formed over the entire substrate surface, asshown in FIG. 7(b).

The substrate was then washed well with an organic solvent (i.e.,chloroform) to remove non-reacted chemical adsorbed material remainingon the substrate surface and then washed with water. Thus, a hydrophilicsiloxane-based monomolecular layer 74 represented by the formula [23];##STR23## was formed such that it was chemically coupled to the surfaceand had a thickness of about 2.5 nm, as shown in FIG. 9(c).

EXAMPLE 10

Subsequent to Example 9, the substrate 81 was dried well and then dippedand held for about two hours in a solution containing 4 wt. % of

    (CH.sub.3).sub.3 SiO-(Si(CH.sub.3).sub.2 O).sub.6 -SiCl.sub.3,

80 wt. % cyclohexane (or n-hexadecanetoluene or xylene or bicyclohexyl),12 wt. % of carbon tetrachloride and 7 wt. % of chloroform. Since thesurface of the monomolecular film 82 contained many hydroxyl groups, adehydrochlorination reaction was brought about between -SiCl groups ateither end of molecules of the material having a plurality ofchlorosilyl (-SiCl) groups at molecule ends and hydroxyl groups of themonomolecular film. A monomolecular layer 83 represented by the formula[24]; ##STR24## was thus formed in a laminated state on themonomolecular film obtained in Example 9.

The substrate was then well washed with an organic solvent to removeexcess surface active material remaining on the substrate surface andthen washed with water. A siloxane-based monomolecular layer 85 was thusformed such that it was chemically bonded to the surface and had athickness about 5.0 nm, as shown in FIG. 8.

When a multi-layer film is desired, the process of Example 8 to 10 maybe repeated for a desired number of layers, and then Example 8 to 10 maybe carried out. By so doing, a siloxane-based lamination monomolecularfilm having a water-repelling surface can be obtained. Further, bycarrying out Example 8 to 10 for the last layer, a laminationmonomolecular film having a hydrophilic surface can be obtained.

As has been shown, the invention is greatly beneficial to the industry.

The invention may be embodied in other specific forms without departingfrom the spirit or essential characteristics thereof. The presentembodiment is to be considered in all respects as illustrative and notrestrictive, the scope of the invention being indicated by the appendedclaims rather than by the foregoing description and all changes whichcome within the meaning and range of equivalency of the claims areintended to be embraced therein.

We claim:
 1. A chemically adsorbed laminated film comprising amonomolecular inner layer film having molecule chains comprising mainlyfluorocarbon groups and Si atoms at opposing ends of the moleculechains, said monomolecular inner layer being fixed onto a substratesurface by covalent -Si- bonds, and a monomolecular outer layer filmhaving molecule chains comprising mainly fluorocarbon groups, saidmonomolecular outer layer being fixed onto the monomolecular inner layerby -Si- bonds.
 2. The chemically adsorbed laminated film according toclaim 1 wherein the fluorocarbon chains of the outer layer containfluorine groups at an outermost end.
 3. The chemically adsorbedlaminated film according to claim 1, wherein the covalent -Si- bonds are-SiO- bonds.
 4. The chemically adsorbed laminated film according toclaim 1, wherein the surface of the outer monomolecular layer compriseshydroxyl groups, said laminated chemically adsorbed film havinghydrophilic and oil-repelling properties.
 5. The chemically adsorbedlaminated film according to claim 1, wherein the surface of the outermonomolecular layer has fluorocarbon groups at an outermost end, saidlaminated chemically adsorbed film having water- and oil-repellingproperties.
 6. The chemically adsorbed laminated film according to claim1, wherein the substrate is made of a member selected from the groupconsisting of metals, ceramics, glass and plastics.